Physical aids are also very helpful when running a campaign. Depending on the genre the aids may change a bit, but most should be consistent. Here a few we use.
1) Hex mat and miniatures. We actually have a square mat, but hex mats would probably be best, since that is easier to see diagonal alignments. All good game stores sell these and if they don't have them in stock, should be able to get you one. Miniatures can also be gotten at game stores. There are a lot of pre-painted miniatures, now, so you don't have to paint them on your own, but games stores will also have non-painted ones and paints to make them as you like. It's fun, after playing a character for a while, to pick a new miniature out for them. This is a handy aid so players can see where they are in relation to other players and the bad guys and there is no confusion as to where they placed that fireball.
2) Hand drawn maps. My husband loves drawing maps for ruins and areas, when he has time. He use to do so when we were college to add spice to where we were going and we loved them. Granted, you can always mislead, (on purpose or accident), your players with such maps, but they are fun to add.
3) Scrolls and other written material. Ransom notes, notes on that secret treasure trove, the secret note to the rival noble, all these are fun to get in physical form and not just described. It adds depth to what your discussing and if you do it enough, sometimes the players may not actually know for sure what is the important part and what is flavor text so you can keep them on their toes.
Next: Notes for the GM